Poisoning, toxic, noxious, or allergenic effect, unspecified

Two employees were fixing a sewer system at the intersection. The first employee went down into the sewer to relieve a blockage. He finished and proceeded to climb the 9-foot ladder up the sewer hole. Just before he was able to reach the top of the hole, he collapsed and fell down the ladder. The second employee went down the ladder to rescue the first employee and put a hoist rope around him. While the first employee was being hoisted up the hole, the second employee succumbed to the gases that were in the sewer and collapsed. One of the employees was hospitalized.